Difficult choice for me between Accel World and Sword Art Online. Love them both! Chose Sword Art Online, because at least that ended nicely and completely, whereas I'm still hopeful for another season to complete Accel World.

Clannad was fun? I guess the first season was fun, kind of your typical harem but still entertaining. Clannad After Story was not fun at all! SAO is always a good one to fall back on as well as Angel Beats! and FF7 Advent Children. It's really whichever shows are your absolute favourites.

Of those its either SAO or High school of the *Dead
Typically I fall back on super heroes, Dragon ball series, conan...I just realized how long this list would be so I guess I don't fall back on one specific series